KR20000011472A - semimelt-injecting method and apparatns of metal - Google Patents

Abstract

PURPOSE: A semi melting injection molding method of a metal and its device are provided to obtain a peel-molded product of the high quality by excellently maintaining the fluidity of a melting pot. CONSTITUTION: The injection molding device(1) comprises:a cylindrical injecting cylinder(2) equipped; a screw(3) installed to be able to rotate and to be able to move inside the injecting cylinder(2); and a hopper(6) to supply resources arranged in the rear part of the injecting cylinder(2), and connected to the injecting cylinder(2) by interposing an argon air chamber(7) filled the argon gas in the hopper(6) to prevent the oxidation by putting the resources inputted into the hopper(6) inside the argon air; a pellet P supplied inside the injecting cylinder(2) from the hopper(6) to be a melting pot M by agitating by the screw(3) and by melting by a heater.

Description

Semi-melt injection method and apparatus therefor {semimelt-injecting method and apparatns of metal}

TECHNICAL FIELD This invention belongs to the technical field regarding the semi-fusion injection molding method and apparatus of the metal which inject | pour the molten metal material into the cavity of a metal mold in semi-melt state, and shape a thin molded article.

Conventionally, as a method of molding a metal molded article having better internal quality than die cast molding, for example, as shown in Japanese Patent Application Laid-Open No. 2-15620, a molten metal material (magnesium alloy) is used as the metal material. The anti-melt injection molding method which inject | pours into the cavity of a metal mold | die in the semi-melt state below the liquidus temperature of is known. In this semi-melt injection molding method, since the molding can be performed at a relatively low temperature, the mold life can be longer than that of the die cast molding, and the molding precision can be improved.

However, when attempting to injection mold a metal thin molded article having a thickness of 1.5 mm or less corresponding to a cavity, the molten metal material is easily solidified in the cavity of the mold because of the thin thickness, so as to prevent it. It is necessary to perform injection of the molten metal. In this case, when high-speed injection is performed by die-casting, a large amount of casting pins is generated and it is uneconomical, and the flow of the molten metal is disturbed and the internal quality is further lowered. Injection molding is suitable.

However, in the semi-molten injection molding method, since the molding is performed in a semi-molten state below the liquidus temperature of the metal material, the fluidity of the molten metal tends to be lowered, and the molten metal may not be reliably filled in the cavity. If the conditions are not set appropriately, it is difficult to apply the semi-fusion injection molding method to the molding of the thin molded article.

The present invention has been made in view of the above, and its object is to melt the metal material by injecting the molten metal material into the mold cavity in a semi-molten state to mold the thin molded article. It is possible to obtain a high quality thin molded article by maintaining a good fluidity of the.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the metal mold | die of the metal half melt injection molding apparatus which concerns on embodiment of this invention.

Figure 2 is a cross-sectional view showing the injection molding machine of the anti-fusion injection molding apparatus

3 is a graph showing the relationship between the ratio d / t and the flow length of the product part average thickness of the solid diameter of the molten metal

4 is a graph showing the relationship between the product gate speed V and the flow length of the molten metal

Fig. 5 is a graph showing the relationship between the value of the solid phase rate Fs × the solid diameter d and the flow length;

6 is a schematic view showing the cavity shape of the mold used in the fluidity test

Fig. 7 is a schematic diagram showing a tongue image of a cavity, such as a mold, used in a specific gravity measurement test;

Fig. 8 is a graph showing the relationship between the ratio to / tg of the product gate portion thickness of the overflow gate portion and the ratio ro / rg of the product gate portion portion ratio of the overflow gate portion portion ratio in the product portion.

9 is a schematic diagram showing the point of the amount of warpage measurement test

10 is a graph showing the relationship between the solid phase rate Fs and the amount of warpage

<Explanation of symbols for main parts of drawing>

11: mold 13: cavity

17: product gate 20: overflow gate

M: molten metal

In order to achieve the above object, in the present invention, the solid phase diameter of the molten metal is set to 0.13 times or less with respect to the average thickness of the product portion of the thin molded article.

Specifically, in the first invention of the present invention, the metal is melted by injecting a molten metal material into a mold cavity through a product gate in a semi-melt state below the liquidus temperature of the metal material to form a thin molded article. It is assumed on the injection molding method.

The average diameter of the solid phase of the molten metal is set to be 0.13 times or less with respect to the average thickness of the product portion corresponding to the cavity in the thin molded article.

That is, when the solid diameter of the molten metal is larger than 0.13 times the average thickness of the product portion of the thin molded article, the fluidity of the molten metal is greatly deteriorated and it is not practical, so it is set at 0.13 times or less. This solid diameter can be easily made small by shortening the molding cycle time. Therefore, a high quality thin molded article can be obtained by a simple method. In addition, the "thin molded article" used here is the value which divided | segmented the volume (unit: mm) of the molded article or product part whose thickness is 1.5 mm or less with the 50% or more part of a product part divided by the surface area (unit: mm <2>) of both sides of the product direction in the thickness direction. The molded article which becomes 0.75 or less is said (it is the same also in the 6th invention of this invention).

In the second invention of the present invention, in the first invention of the present invention, the product gate speed of the molten metal is set to 30 m / s or more.

In other words, if the product gate speed of the molten metal is less than 30 m / s, the fluidity of the molten metal is greatly reduced, and therefore it is set to 30 m / s or more. Therefore, the quality of the thin molded article can be further improved.

In the 3rd invention of this invention, in the 1st or 2nd invention of this invention, the solid phase rate Fs% of a molten metal is set so that Fs * d <= 1500 may be set as dmicrometer as the solidus diameter of the said molten metal.

That is, when the value of Fsxd is larger than 1500, the fluidity of the molten metal decreases rapidly, and therefore it is set to 1500 or less. Therefore, the effect of the 1st or 2nd invention of this invention can be heightened further.

In the 4th invention of this invention, in the 3rd invention of this invention, the solid phase rate of a molten metal is set to 3 to 40%.

That is, when the solidity rate of a molten metal is less than 3%, the curvature amount of the product part of a thin molded article becomes large too much, and when larger than 40%, it exists in the tendency for the fluidity | liquidity of a molten metal to deteriorate, and is set to 3 to 40%. Therefore, the deformation amount can be suppressed small while maintaining the quality of the thin molded article satisfactorily.

In the fifth invention of the present invention, in the first invention of the present invention, an overflow gate is formed on the side opposite to the product gate with respect to the cavity in the mold, and the overflow gate portion corresponding to the overflow gate in the thin molded article is provided. The thickness is set to 0.1 to 1.0 times the thickness of the product gate portion corresponding to the product gate.

That is, if the thickness of the overflow gate portion of the thin molded article is less than 0.1 times the thickness of the product gate portion, air escape to the overflow groove formed continuously in the overflow gate becomes insufficient, whereas if it is larger than 1.0 times, The molten metal is more likely to be filled in the overflow groove first, and the opening of air is blocked by the molten metal, and the internal quality of the portion near the overflow gate in the product portion of the thin molded product is lowered, so it is set to 0.1 to 1.0 times. Therefore, the air bleeding to an overflow groove can be performed favorably, and the quality of the whole product part of a thin molded article can be improved.

In accordance with a sixth aspect of the present invention, a molten metal injection molding is performed in which a molten metal material is injected into a cavity of a mold through a product gate in a semi-molten state below the liquidus temperature of the metal material to form a thin molded article. Invention of the device.

In this invention, the solid diameter, which is the average diameter of the solid phase of the molten metal, is set to 0.13 times or less with respect to the average thickness of the product portion corresponding to the cavity in the thin molded article. By doing in this way, the effect similar to the 1st invention of this invention can be acquired.

In the seventh invention of the present invention, in the sixth invention of the present invention, the product gate speed of the molten metal is set to 30 m / s or more. Thereby, the effect similar to the 2nd invention of this invention can be acquired.

In the eighth invention of the present invention, in the sixth invention of the present invention, the solid phase rate Fs% of the molten metal is set to satisfy Fs × d ≦ 1500 with the solid phase diameter of the molten metal as d μm. . Thereby, the effect similar to the 3rd invention of this invention can be acquired.

In the ninth invention of the present invention, in the eighth invention of the present invention, the solid phase rate of the molten metal is set to 3 to 40%. By doing in this way, the effect similar to the 4th invention of this invention can be acquired.

In the tenth invention of the present invention, in the ninth invention of the present invention, an overflow gate is formed on the side opposite to the product gate in the mold, and the overflow gate corresponding to the overflow gate in the thin molded article. It is assumed that the thickness of the part is set at 0.1 to 1.0 times the thickness of the product gate part corresponding to the product gate. Thereby, the effect similar to the 5th invention of this invention can be acquired.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. 1 and 2 show an anti-melt injection molding apparatus for a metal according to an embodiment of the present invention, and the anti-melt injection molding apparatus includes an injection molding machine 1 and a mold 11 having a cavity 13. And the molten metal M of the metal material is injected into the cavity 13 of the mold 11 in a semi-melt state below the liquidus temperature of the metal material to form a thin molded article. The part corresponding to the said cavity 13 of this thin molded article becomes a product part. In addition, in this embodiment, a "thin molded article" means the shaping | molding (unit: mm) of the molded article which is 1.5 mm or less in thickness of 50% or more of a product part, or the surface area of the both sides in the thickness direction of a product part (unit: mm <2>). Refers to the molded article divided by.

As shown in Fig. 2, the injection molding machine 1 has a cylindrical injection cylinder 2, and inside the injection cylinder 2, the screw 3 is rotatably and retractably provided. have. Moreover, the nozzle 4 is integrally attached to the front-end | tip part of the said injection cylinder 2. As shown in FIG.

In the upper part of the rear end part of the said injection cylinder 2, the hopper 6 which throws in a raw material is arrange | positioned, This hopper 6 is an injection cylinder 2 through the argon atmosphere chamber 7 filled with argon gas. Is connected to. In this way, the raw material introduced into the hopper 6 is placed in an argon atmosphere to prevent oxidation thereof. In this embodiment, a pellet P in the form of a cutting powder made of magnesium alloy is used as a raw material.

Although not shown in the outer periphery of the injection cylinder 2 and the nozzle 4, a heating heater is provided, and the pellet P supplied from the hopper 6 into the injection cylinder 2 is supplied to the screw 3. While stirring, it is melted by the heating heater to form molten metal M. This molten metal M is a semi-molten state below the liquidus temperature of magnesium alloy, and consists of a solid phase and a liquid phase. The solid-state diameter d, which is the average diameter of the solid phase of the molten metal M, is set at 0.13 times or less with respect to the average thickness t of the product portion of the thin molded article. That is, when the solid-state diameter d of the molten metal M is larger than 0.13 times the average thickness t of the product part of the thin-molded article, the fluidity of the molten metal M is greatly deteriorated and is not practical, so it is set to 0.13 times or less. This solid-state diameter d can be adjusted by the cycle time of molding (that is, the time that the molten metal M stays in the injection cylinder 2). That is, if the cycle time of molding is lengthened, solid phases may coalesce and solid phase diameter d may be enlarged.

The solid phase rate Fs (= solid phase amount / (solid phase amount + liquid phase amount) × 100%) of the molten metal M can be changed by adjusting the heating temperature of the heating heater, and the unit of the solid-state diameter d of the molten metal M is determined. As a micrometer,

Fs × d≤1500

Is set to meet. That is, when the value of Fsxd is larger than 1500, the fluidity of the molten metal M is sharply lowered, so it is set to 1500 or less.

Moreover, the solid phase rate Fs of the molten metal M is set to 3 to 40%. That is, when the solid-state rate Fs of the molten metal M is smaller than 3%, the temperature of the molten metal M is high and the amount of warpage of the product portion of the thin molded article is too large (greater than 0.3 mm). Since it tends to deteriorate, it is 3 to 40%.

At the rear end of the injection cylinder 2, a high speed injection mechanism 9 for advancing the screw 3 to eject the molten metal M from the nozzle 4 is provided. That is, as the pellets P to M are pushed forward of the screw 3, the screw 3 retreats at that pressure (moreover, since magnesium does not have a higher viscosity than that of the resin material, the screw 3 is driven by hydraulic pressure). Helping with the retreat). When retreating by a predetermined distance (the distance corresponding to the amount of molten metal M required for one injection), the high speed injection mechanism 9 is configured to advance the screw 3 to its original position.

As shown in FIG. 1, the tip end of the nozzle 4 is connected to the lower part of the mold 11. The mold 11 is composed of a stationary die 11a fixed to the stationary plate 12 and a movable die 11b that folds against the stationary die 11a. The die 11a is fixed in the mold clamping state. ) And the movable die 11b to form a cavity 13 having substantially the same shape as the product part of the thin molded article. As a result, the average price of the fixed mold 11a and the movable mold 11b in the cavity 13 is almost equal to the average thickness t of the thin molded article.

Between the nozzle 4 and the cavity 13, the spool 15, the runner 16, and the product gate 17 are formed in order from the nozzle 4 side. On the other hand, in the mold 11, the overflow groove 21 is formed on the opposite side (upper side) of the product gate 17 to the cavity 13 via the overflow gate 20, and the cavity 13 is formed. The air inside is discharged to this overflow groove 21.

The product guide 17 and the overflow gate 20 are clamped together in the thickness direction of the product portion of the thin molded article, and the clearance amount between the fixed die 11a and the movable die 11b in the overflow gate 20. In other words, the thickness t ₀ of the overflow gate portion corresponding to the overflow gate 20 of the thin molded product is a gap amount between the fixed mold 11a and the movable mold 11b in the product gate 17, and eventually, the thickness of the thin molded article. The thickness tg of the product gate portion corresponding to the product gate 17 is set at 0.1 to 1.0 times. That is, if the overflow gate thickness to is less than 0.1 times the product gate thickness tg, air escape to the overflow groove 21 becomes insufficient, whereas if it is larger than 1.0 times, the molten metal M first overflows. (21) becomes easy to be filled, and the molten metal M is clogged, and since the internal quality of the part near the overflow gate 20 in the product part of a thin molded product falls, it sets to 0.1-1.0 times.

The molten metal M is injected into the cavity 13 by the high speed injection mechanism 9 from the nozzle 4 via the spool 15, the runner 16, and the product gate 17 to form a thin molded article. have. At this time, the product gate speed (speed at the product gate 17) V of the molten metal M is set to 30 m / s or more. That is, when the product gate speed V of this molten metal M is smaller than 30 m / s, since the fluidity | liquidity of the molten metal M will fall largely, it sets to 30 m / s or more.

To mold the thin molded article using the above semi-molten injection molding apparatus, first, pellets P of magnesium alloy are introduced into the hopper 6, and the pellets P are rotated to knead the pellets P supplied in the injection cylinder 2. While pushing, push it in the direction of the nozzle 4 (forward). In the meantime, the pellet P is heated by a heating heater to become a molten metal in a semi-melt state, and the screw 3 retreats by pressure and hydraulic pressure generated at that time.

When the screw 3 retreats by a predetermined distance, the rotation of the screw 3 is stopped, and the high speed injection mechanism 9 is operated to advance the screw 3. As a result, the molten molten metal M is injected and charged from the nozzle 4 into the cavity 13 and the like of the mold 11. At this time, the solid-state diameter d of the molten metal M is 0.13 times or less with respect to the average thickness t of the product part of the thin-molded product, the product gate speed V of the molten metal M is 30 m / s or more, and the solid-state fraction Fs of the molten metal M is Fs ×. Since each is set to satisfy d≤1500, the fluidity of the molten metal M can be maintained satisfactorily. In addition, since the overflow gate thickness to of the thin-molded article is set to 0.1 to 1.0 times the product gate thickness tg, air can be reliably evacuated in the cavity 13. As a result, the molten metal M is surely filled in the cavity 13.

Then, the molten metal M is cooled and solidified, the mold 11 is opened to demold the thin molded article, and then unnecessary portions other than the product portion of the thin molded article are cut. The internal quality of the product part of the thin molded article thus obtained is equally good in any part. Moreover, since the solid phase rate Fs of the molten metal M is set to 3 to 40%, the deformation amount can be suppressed small, maintaining the quality of a product part favorable.

In addition, the solid-state diameter d of the molten metal M is 0.1 times or less with respect to the average thickness t of the product portion of the thin-molded article, the product gate speed V of the molten metal M is 50 m / s or more, and the solid phase rate Fs of the molten metal M is Fs × d. When setting so that it may satisfy <= 800, the fluidity | liquidity of the molten metal M is further improved and it is preferable.

The anti-melt injection molding apparatus according to the above embodiment is suitable for molding a thin molded article made of magnesium alloy, but can also be applied to other metals (particularly aluminum alloys).

Next, the Example concretely implemented is demonstrated.

First, as shown in Table 1, two kinds of magnesium alloys (alloy A and alloy B) having different chemical compositions were produced.

Chemical composition (wt%) Al Zn Mn Fe Ni Cu Mg Alloy A 6.2 0.9 0.23 0.003 0.0008 0.001 Remainder Alloy B 8.9 0.7 0.24 0.003 0.0008 0.001 Remainder

Next, the fluidity of the molten metal was investigated using the said alloy A and the alloy B. That is, as shown in FIG. 6, the cavity 27 of a metal mold | die is formed in S shape, the molten metal 28 is injected into the cavity 27 from the nozzle of an injection molding machine, and it filled in the cavity 27. As shown in FIG. The fluidity | liquidity was evaluated by the length (flow length) from the product gate of the molten metal 28 to the front-end | tip part. Then, the case where the ratio d / t of the solid part diameter of the molten metal 28 to the product part average thickness is changed, when the product gate speed V of the molten metal 28 is changed (alloy B only), and the solid phase rate Fs ( When the value of%) x solid-diameter d (micrometer) was changed (alloy B only), it investigated how the flow length converts, respectively.

The results of the fluidity test are shown in FIGS. 3 to 5, respectively. 3 shows that when d / t is larger than 0.13, the fluidity deteriorates rapidly, while when d / t is 0.1 or less, the fluidity is stable and satisfactory. From Fig. 4, when V is smaller than 30 m / s, the fluidity is very bad, whereas when V is 50 m / s or more, the flow length exceeds 200 mm, which is considered empirically desirable, and it is possible to obtain a surely high quality. I know it is. 5 shows that when the value of Fs × d is larger than 1500, the fluidity is drastically reduced. On the other hand, when the value of Fs × d is 800 or less, the flow length exceeds 200 mm, which further improves the quality. Can be.

Next, as shown in FIG. 7, the cavity 30 of the metal mold | die was formed in substantially rectangular box shape of 120 mm x 70 mm x 1 mm. In Fig. 7, (31) is a product gate, (32) is an overflow gate, and (33) is an overflow groove. Then, by changing the ratio to / tg with respect to the product gate part thickness of the overflow gate part thickness, the portion near the overflow gate 32 (the part from the overflow gate 32 to 10 mm) in the product part is changed. It was investigated how the ratio γo / γg to the specific gravity γg of the portion near the product gate 31 (part from the product gate 31 to 10 mm) of the specific gravity γo changes.

The results of the specific gravity test are shown in FIG. 8. As a result, when to / tg is larger than 1.0, it turns out that (gamma) o / (gamma) g falls. As a result, the decrease in γo / γg is thought to be due to gas entering into the vicinity of the overflow gate because gas is hard to enter in the vicinity of the product gate and its specific gravity is stable. Therefore, when to / tg is too big | large, air escape to an overflow groove will worsen, and the quality of the part near the overflow gate of a product part will fall.

Next, how the amount of warpage of the product portion of the molded article molded by the mold of FIG. 7 is changed by the solid phase rate Fs was investigated. The amount of warpage was measured by how much the mass center portion of the product portion deviated from the reference line connecting both ends, as shown in FIG. 9.

The results of the warpage amount measurement test are shown in FIG. Thereby, when Fs is less than 3%, the curvature amount exceeds 0.3 mm, and the use problem of a molded article increases.

As described above, according to the first or sixth invention of the present invention, in the case of molding a thin molded article by injecting a molten metal material into a mold cavity in a semi-molten state, a solid diameter, which is an average value of the solid phase of the molten metal, is formed. By setting it to .13 times or less with respect to the average thickness of the product part corresponding to the cavity in a thin molded article, the fluidity | liquidity of a molten metal can be improved and quality improvement of a thin molded article can be aimed at.

According to the second or seventh invention of the present invention, the quality of the thin molded article can be further improved by setting the product gate speed of the molten metal to 30 m / s or more.

According to the 3rd or 8th invention of this invention, 1st invention of this invention is set by setting the solid-state rate Fs% of a molten metal so that Fsxd <1500 may be set with the solidus diameter of the said molten metal as dmicrometer. Alternatively, the effect of the second invention can be further enhanced.

According to the 4th or 9th invention of this invention, by setting the solid-state rate of a molten metal to 3 to 40%, the deformation | transformation can be suppressed, maintaining the quality of a thin molded product favorable.

According to the fifth or tenth aspect of the present invention, in the mold, an overflow gate is formed on the opposite side to the product gate in the cavity, and the thickness of the overflow gate portion corresponding to the overflow gate in the thin molded product is determined by the product gate. By setting the thickness at 0.1 to 1.0 times the thickness of the product gate portion corresponding to the above, it is possible to satisfactorily release the air from the overflow groove so that the entire product portion of the thin molded article can be made of high quality.

Claims (10)

In the method of semi-molten injection molding of metal in which the molten metal of the metal material is injected in a semi-melt state below the liquidus temperature of the metal material through a product gate through a product gate to form a thin molded article, The solid-state diameter, which is the average diameter of the solid phase of the molten metal, is set at 0.13 times or less with respect to the average thickness of the product portion corresponding to the cavity in the thin molded article. The method of claim 1, An anti-melt injection molding method for metals, characterized in that the product gate speed of the molten metal is set to 30 m / s or more. The method of claim 1, The solid phase rate Fs% of the molten metal is dμm as the solid diameter of the molten metal. Fs × d≤1500 Injection molding method for the reaction of a metal, characterized in that the setting to meet. The method of claim 3, An anti-melt injection molding method for metals, wherein the solid phase rate of the molten metal is set to 3 to 40%. The method of claim 1, In the mold, the overflow gate is formed on the opposite side of the product gate to the cavity, The thin melt molded article, wherein the thickness of the overflow gate portion corresponding to the overflow gate is set to 0.1 to 1.0 times the thickness of the product gate portion corresponding to the product gate. In the semi-molten injection molding apparatus of the metal material, the molten metal material is injected in a semi-melt state below the liquidus temperature of the metal material through a product gate through a product gate to form a thin molded article, The solid-state diameter, which is the average diameter of the solid phase of the molten metal, is set at 0.13 times or less with respect to the average thickness of the product portion corresponding to the cavity in the thin molded article. The method of claim 6, An anti-fusion injection molding apparatus for metal, characterized in that the product gate speed of the molten metal is set to 30 m / s or more. The method of claim 6, The solid phase rate Fs% of the molten metal is dμm as the solid phase diameter of the molten metal. Fs × d≤1500 Semi-fusion injection molding apparatus of metal, characterized in that set to meet. The method of claim 8, An anti-fusion injection molding apparatus for metal, wherein the solid phase rate of the molten metal is set to 3 to 40%. The method of claim 9, In the mold, an overflow gate is formed on the side opposite to the product gate with respect to the cavity, In the thin molded article, the thickness of the overflow gate portion corresponding to the overflow gate is set to 0.1 to 1.0 times the thickness of the product gate portion corresponding to the product gate.